2009ip 2019com

IC 4712

Harrison J. Abbotharrison.abbot@anu.edu.au

NGC 7259

Supernovae are incredibly bright events that can be seen at extragalactic distances away. By studying their early light curves, we will be able to see early shock events such as shock breakout occur, which can reveal a lot about their progenitor systems. WiFeS is an integral field spectrograph mounted to the ANU 2.3m telescope at Siding Springs Observatory. We have utilised WiFeS to follow up on several young, nearby supernovae that occured within the TESS fields during its southern cycle. Through this program, we have tracked the spec-tral evolution of shock events unfold. One such case, SN2019com, is shown below. TESS’s high cadence readouts, and large field of view, provide us with an opportunity to study suhigh cadence readouts, and large field of view, provide us with an opportunity to study su-pernovae using a previously underutilised tool; shock physics.

Shock breakout is the first visible cue of a supernova detonation.WhenWhen supermassive stars run low on fusable material, they start to implode due to gravity. The fusion reaction occuring within produces a shock front, which is trapped by the imploding outer layers. As more material gets absorbed by the core, the outer layers become optically thin, and finally allow the shock front to propagate outwards. This releases a quick, bright burst of high energy light called ‘Shock Breakout’. By studying the shock breakout, and resul-tant shock cooling phase of SN, we can obtain a lot of information about the progenitor system. Variables such as the progenitor radius, ejecta mass, and ejecta velocity can all be de-termined by applying Piro’s or Waxman’s model of shock breakout.

Supernova imposters are a rare occurance. ThoughtThought to be the result of a Luminous Blue Variable star undergoing huge outbursts, these objects are often flagged as SN multiple times prior to final detonation. These outbursts pump large amounts of matter into the surrounding circumstellar material (CSM), leading to a SN IIn spectrum. The first case of a supernova imposter, SN2009ip, is detailed below. Through our program, we have managed to obtain spectra of shock cooling in a 2009ip-like SN.

Real Time Detection of Supernova Shock Physics

with TESS

Applying Piro’s model of Shock Breakout to the shock cooling data points of 2019com reveals:

r ~ 110 Msolarmejecta ~ 3 Msolarvejecta ~ 10400 km/stbreakout ~ 5 days prior to first datum point

These values are in agreeance with an These values are in agreeance with an LBV progenitor system, just like 2009ip.

We have obtained spectra from tbreakout giving us a glimpse into how the early shock physics unfolds.Time

Magnitude

* Days from t0

t = 21*

t = -1*

t = 24*

t = -4*

Fe I / Fe II

Hα

He IHe I

HβHγHδ

Prominent Hα Typical of Type II SN. FWHM measurement reveals two Gaussians overlayed.

For 2019comvvCSM ~ 211 km/svejecta ~ 10,400 km/s

Vanishing HeHelium lines which are apparent at early epochs vanish at later dates. Helium is unexpected from SN unexpected from SN IIn, and indicates a dense CSM.

Broad Fe Both SN show a broad iron emission lines approximately 20 days approximately 20 days after shock breakout. This is an atypical fea-ture for a SN IIn to display

Blue ExcessA blue excess is fairly A blue excess is fairly typical of SN and acts as an indicator that the supernova is indeed young. By analysing the gradient of the early time spectra, we can ascertain the temcan ascertain the tem-perature of the shock front by comparing with the black body emission curve.